I have previously complained about the performance of goto anything during typing a filename, but it actually seems worse with the new retina 15". The performance is bad even when not previewing a new file, which makes me think the only logical answer is that sublime is rendering off-screen text for items in that list. The hardware in this thing struggles to render text as it is (sublime scrolls worse than on my 2009 13" macbook pro), so would potentially cause the huge impact I'm seeing.

When typing a filename which matches quite a few results, and keeping that file at the top of the list (by continuing to type the filename) I get an update every 0.5s or so. I can make a video if necessary.

Okay, after making a video to show this happening, I did find that removing my installed plugins/packages made it a hell of a lot faster, though there is still some latency (which is probably just the document preview rendering — would still love a toggle for that). I will include the video as the text rendering/scroll speed is no different with or without plugins: http://youtu.be/QRa7v1R7khk?hd=1. I've done a short write-up on what I have noticed so far OS-wide if anyone is interested: http://whrl.pl/RdeQvl

It's definitely not fill rate, but more to do with the rendering of text. So any kind of caching of text will help. I'm guessing Apple will release some kind of documentation regarding this at some point, considering how well they optimised Safari 6.

Unless there's something fundamentally wrong in the OS X graphics pipeline, it's almost certainly CPU fill rate. With 4 times as many pixels as most applications are tested with, that's going to be the component that gets stressed. The GPU will have no issues moving that many pixels, but it doesn't help applications that rely on the CPU for rendering, which is most of them, including Sublime Text.

There are 4 cpu cores with 2 hyper threads each though and blitting graphics is a ridiculously parallelizable task. So if you "own" those routines rather than relying on a library there's much that can be done.

As for using the gpu instead, not knowing any details of how text rendering is implemented in ST2 couldn't you just cache the glyphs to 1 or more altas textures and blit using gl?

You could also draw the curves with triangles using special texture coordinates and shaders as described in GPU Gems 3 which is quite clever IMO. I stumbled upon a piece of code converting ttf-fonts to a format suitable to be rendered that way that looks interesting for my own projects. It's in a need for some cleanup before it's usable to me though. I'll post a github link once I've cleaned it up enough to compile and I have a small test working.